194 HARVARD LAW REVIEW. of law governing the armed forces of the State, and the administra- tion of its other departments ; laws regulating particular trades and undertakings in the interest of public health or safety; and, in short, all State enterprise and all active interference of the State with the enterprises of private men. We say active interference. For there are many dispositions in particular departments of priv- ate law which are founded on reasons of public policy, but are left for the parties who may profit or be relieved by them to bring to the notice of the courts. Of this kind are certain special restrictions on freedom of contract. In countries under the com- mon law the State does not interfere of its own motion to prevent an agreement from being enforced on the ground that it is " in restraint of trade." On the other hand, there are many legislative enactments which expressly or by necessary implication forbid certain kinds of contracts to be made. Such enactments appear to belong to public law, though it is often convenient or necessary to consider them in connection with the rules of private law whose usual operation is excluded or limited by them. To public law, too, belong all the minor penal enactments inci- dent to constitutional and departmental legislation. But public law does not even here hold the field alone, for the same legislation which creates new public duties and imposes penalties may well, under specified conditions, also confer new rights to redress on individuals either expressly or as a consequence of principles recognized by the courts. The extent and effect of any such prin- ciples cannot be laid down beforehand : it depends on the forms, methods, and history of the particular system of law which is being administered. In our law the violation of a public duty may often give a right of action to a citizen who has thereby suffered damage, but this is by no means a universal or necessary result.^ It will be seen, therefore, that the topics of Public and Private Law are by no means mutually exclusive. On the contrary, their application overlaps with regard to a large proportion oi the whole mass of acts and events capable of having legal consequences. Sometimes the distinction between public and private law is made to turn on the State being or not being a party to the act or proceeding which is being considered. Only dealings between subject and subject, it is said, form the province of private law. But this does not seem quite exact; unless, indeed, we 1 Ward V. Hobbs (1878), 4 App. Cas. 13.
